Positive integers that do not have a primitive root.

Terms

a(0) =8a(1) =12a(2) =15a(3) =16a(4) =20a(5) =21a(6) =24a(7) =28a(8) =30a(9) =32a(10) =33a(11) =35a(12) =36a(13) =39a(14) =40a(15) =42a(16) =44a(17) =45a(18) =48a(19) =51a(20) =52a(21) =55a(22) =56a(23) =57a(24) =60a(25) =63a(26) =64a(27) =65a(28) =66a(29) =68